The use of personal watercraft has grown widely, and particularly the use of water jet powered watercraft, such that on any given weekend a great number of personal watercraft, to include jet skis, jet-boats and runabouts can be found in use. Each of these watercraft features a hull with a water jet drive assembly housed therein. In known fashion, the water jet drive assembly is powered by an engine operably connected to a twist grip or trigger-type throttle similar in function and appearance to that used in a motorcycle or an ATV, for example. The throttle is grasped by the hand of the watercraft operator and twisted or squeezed into a "throttle-on" position in which the engine is powered to the desired level or speed. The engine is operably coupled to a pump or an impeller for creating a pressurized water jet in the throttle-on position, the water jet being directed outwardly and away from the hull by a water jet nozzle pivotally supported on the hull of the watercraft. The water jet thus propels the watercraft in the throttle-on position. In the "throttle-off" position the engine is reduced to idle speed and the watercraft is not otherwise propelled by the water jet drive.
The water jet nozzle has two functions, the first of which, as described above, is to focus or direct the water jet in the throttle-on position in a direction away from the watercraft for propelling the watercraft. The second function of the nozzle is to steer the watercraft in the throttle-on position. If the operator falls off the watercraft during use, the throttle will automatically return to the throttle-off position and will reduce the engine speed to idle or turn the engine off. As personal watercraft are steered by the water jet as it passed through the water jet nozzle, however, if the water jet drive is throttled off it can become difficult to steer the watercraft in that these types of watercraft are not typically provided with separate rudders attached to any kind of steering device. When this occurs, therefore, it becomes difficult to efficiently, and at times safely, steer the watercraft, if at all, in the throttle-off position.
A common scenario in which this problem occurs is when a person riding a jet ski, for example, suddenly throttles-off in order to avoid colliding with another watercraft, a dock, the shore line, and/or a swimmer. The natural tendency when such an event occurs is to reduce the speed of the watercraft by throttling-off and attempting to steer the watercraft around the obstacle. If, however, the throttle of a typical personal watercraft is reduced to the throttle-off position, the operator of the watercraft suddenly loses the ability to efficiently steer the watercraft due to the loss of the dual purpose propulsion and steering water jet, and a collision may thus become inevitable as the watercraft, which is still moving at speed due to its momentum, cannot be safely steered without the water jet being passed through the nozzle of the drive assembly.
An auxiliary rudder for a jet propulsion unit is disclosed in U.S. Pat. No. 3,982,494 to Posti, which discloses a rudder moved by a hydraulic cylinder powered by a hydraulic pump and moved into a retracted position when the watercraft is operated, i.e., when it moves or is propelled at speed. The rudder assembly is constructed such that when the watercraft is moving at a sufficiently high speed a sufficient amount of water pressure is generated to supply the pump used to power the hydraulic cylinder. At speed, therefore, the pump and cylinder move the rudder into an inoperative position. If, however, the throttle is suddenly moved into a throttle-off position, for example when trying to avoid an obstacle, the watercraft will continue at speed in that it will not immediately stop. Accordingly, as sufficient water pressure still exists to keep the cylinder pumped up, the rudder will not drop down until the speed of the watercraft diminishes to the point that the water pressure is insufficient to pump the hydraulic cylinder at a force sufficient to keep the rudder in its inoperative position. Thus the rudder will only be allowed to fall into its operative position at slow speeds. By the time the rudder may be lowered, however, it may too late in that the operator of the watercraft may have already struck or passed over the obstacle prior to losing enough speed to avoid the collision.
Another rudder assembly is disclosed in the abstract of Japanese Patent Application No. 64-103253 of Kobayashi, which illustrates a rudder that is displaced upwardly when the boat strikes or runs over a shoal. The rudder is also moved upwardly into a retracted or inoperative position by the water pressure of the boat moving at a high speed, whether or not the boat is actually being propelled at that time. Again, therefore, in a throttle-off position in which there is a time lag between the throttling-off of the water jet drive and the time the watercraft loses enough speed (water pressure) to allow the rudder to extend into an operative position, the possibility exists that the obstruction which the operator of the watercraft is seeking to avoid may be struck.
What is needed, therefore, but seemingly unavailable in the art, is a retractable rudder assembly for use with a personal watercraft that will not interfere with the operation of the watercraft at a throttle-on position when the watercraft is moving at speed, but which will reliably and quickly extend downwardly into an operative position when the throttle of the drive assembly is moved into the throttle-off position, regardless of the boat speed, so that the operator of the personal watercraft retains the ability to steer the watercraft when the water jet drive is not otherwise propelling the watercraft.